The proposed studies will extend and refine investigations of the potential of a variety of demonstrably abundant airborne biological particles to cause immunologically mediated human health effects. Pollens, including those of pines and other conifers, will be evaluated critically through skin and mucosal testing with suitable extracts. Major effort will be concentrated, using similar methods, on spores of select ascomycetes, basidiomycetes and myxomycetes derived from field sources or laboratory-grown. Specific deuteromycete taxa including Pithomyces and Torula as well as locally abundant oomycetes will be studied also. Volumetric air sampling will be continued to better define the prevalence and phenology of these varied types. Morphological criteria for spore identification will be defined using material from field and herbarium sources studied by light and scanning electron microscopy. Optimal methods for preparing fungus extracts will be sought using preparations of spores, mycelia and cultural substrates. In related work, allergenic relations among the emanations of fungi will be studied using immunosorbents. Cultural sampling (and non-viable collections) will be emphasized in studying the fungus and actinomycetous flora of humidifying devices and the interiors that house them. A survey of thermophiles in free air will also be undertaken. Particle removal by window air conditioners will be evaluated and these devices studied as possible aeroallergen sources. Using differential filtration and immunological assay, pollen allergens will be sought in atmospheric fractions below 10 micra.